U.S. officials are discussing with Middle East governments the steps needed to ensure that Syria's chemical and biological weapons sites are secured when President Bashar al-Assad leaves office, Defense Secretary Leon Panetta said Thursday.

"We're not talking about ground troops, but it depends on what ... happens in a transition," he told reporters.

Asked whether he had ruled out putting U.S. troops in Syria to secure such weapons, Panetta said: "You always have to keep the possibility that, if there is a peaceful transition and international organizations get involved, that they might ask for assistance in that situation. But in a hostile situation, we're not planning to ask for that."

Preventing Syria from using chemical weapons once its military has moved to use them "would be almost unachievable," said U.S. Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff.

"You would have to have such clarity of intelligence, you know, persistent surveillance, you'd have to actually see it before it happened, and that's unlikely, to be sure," Dempsey said.

The discussion came as the Syrian government accused the diplomat leading the international effort to forge peace of being biased in favor of the enemies of Damascus.

Lakhdar Brahimi, the U.N. and Arab League joint special envoy to Syria, has "deviated from the essence of his mission and clearly unveiled his bias to circles known for conspiring against Syria and the interests of the Syrian people who have not read the political program for solving crisis objectively," a state report said.

The state-run Syrian Arab News Agency quoted an official source at the Foreign and Expatriates Ministry.

Syria's remarks came after the BBC interviewed Brahimi, who has been trying to persuade the government and rebels to cease hostilities and to urge world powers to move toward a political settlement and end a civil war that has killed more than 60,000 people.

Brahimi told the BBC that al-Assad told him last month that "he was thinking of taking a new initiative." Brahimi was quoted as saying he told al-Assad that "it would have to be different from initiatives in the past ... which had not changed the situation one iota."

But, Brahimi said, "what has been said this time is not really different. It is perhaps even more sectarian, more one-sided."

Brahimi is scheduled to meet with Russian Deputy Foreign Minister Mikhail Bogdanov and U.S. Deputy Secretary of State William Burns at the U.N. offices in Geneva, Switzerland, on Friday.

Washington backed up the diplomat. "From our perspective, Special Envoy Brahimi was simply giving voice to the same sentiments that we've heard from Syrians across this political spectrum, that 40 years of the Assad family is enough," U.S. State Department spokeswoman Victoria Nuland told reporters Thursday.

In a public address on Sunday, al-Assad laid out a plan to solve the crisis, which he said should start with regional countries ending their support for "terrorists." The government frequently uses that term to describe dissidents.

It includes a national dialogue and the writing of a new constitution that would be put up for a public referendum. A major caveat to the plan: Al-Assad said he will not deal with "terrorists."

Brahimi said that al-Assad told him he was considering running again next year for president. Al-Assad and his late father, Hafez, before him have run Syria for decades.

"I think what people are saying is, a family ruling for 40 years is a little bit too long," Brahimi said, according to the BBC.

Brahimi said al-Assad has discussed a transition, "but whether he means the transition that is needed is uncertain."

The Syrian source said Damascus "expected the U.N. envoy to read and analyze the political program for solving the crisis, which we provided his office in Damascus with a copy of, as the only way out of the crisis, for it is based on the comprehensive dialogue among all elements of the Syrian society to agree on a national pact to be put to referendum and charts the political, economic and judicial system of Syria on democratic pluralistic bases."

Top British diplomat: "All options are on the table"